phpMoneyBooks is a PHP/MySQL program that aims to be a Web-based QuickBooks replacement. It can manage bank accounts and check registries; manage customers and create statement charges; print statements to bill customers; and display profit and loss reports. The design is modular so that features can be added by any PHP/MySQL developer. With new modules, you can direct the user to a URL. Clients can log in and check their own bills and pay online, create memorized billing cycles with Auto Billing (good for recurring billing), and more.

The Integrated Financial System (ifs) is a financial software package to help you keep track of your coins! IFS is intended to be used by those who want to keep track of their money in a detailed way. It is useful for people who are taking control of their financial lives and want more features than what a spreadsheet can offer. The software package is suitable for individuals, families, and small-to-medium sized businesses. Main features include recording and tracking of expenses; support for muliple users and multiple currencies; a reporting suite; configuration tools for administrative tasks; permissions system to segregate duties and protect sensitive information; and a complete sample data scenario to evaluate the entire package.

MibianLib is an options pricing library offering the ability to calculate the price, the implied volatility, the Greeks or the put-call parity of an option using the Garman-Kohlhagen, Black-Scholes, and Merton models.

Skrooge is a personal finances manager powered by KDE. It allows you to keep track of your expenses and income, categorize them, and build reports. You can also manage your investments and see how they perform over time. Multiple accounts are supported. Some of the features included are advanced graphical reports, tabs that help you to organize your work, infinite undo/redo (even after the file was closed), instant filtering on operations and reports, infinite category levels, mass update operations, scheduled operations, tracking of refunds, automatic processing based on search conditions, and support for multiple currencies.

The OpenGamma Platform is a unified system for front-office and risk calculations for financial services firms. It combines data management, a declarative calculation engine, and analytics in a single comprehensive solution.

Moneychanger is a GUI built on top of Open Transactions, a financial crypto library. Moneychanger can be used to create pseudonyms, issue currencies, open accounts, withdraw and deposit cash (untraceable digital cash), write and deposit cheques, trade on markets, and much, much more.

Bitcoin is a peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending.